The Framework for K-12 Science Education and the Next Generation Science Standards (NGSS) describe an approach to science education that explicitly integrates three dimensions of the scientific endeavor- Science and Engineering Practices, Disciplinary Core Ideas, and Crosscutting Concepts. A major challenge to implementing this vision is the lack of NGSS-aligned curriculum materials and teachers' need for professional development that builds their ability to effectively implement this new approach to instruction. To address the curriculum need, the Genetic Science Learning Center (GSLC) at the University of Utah will utilize the experience it has gained over the past three years in developing NGSS-aligned curricula as well as its award-winning expertise in developing effective, interactive, multimedia learning experiences, to produce two new life science curriculum units. The goals of the Genes and Microbes: Engaging Students and Teachers in NGSS-Aligned Curricula and Professional Development project are to: GOAL 1: Educate secondary-level students about the impacts of genes and microbes on health and disease so that they can make informed choices related to their health. Objective 1: Produce two curriculum units that each address the three dimensions of the NGSS. Objective 2: Evaluate the efficacy for student learning of the two curriculum units using small-scale randomized controlled trials. GOAL 2: Prepare teachers to use the two curriculum units through online professional development courses, and workshops at the state, regional and national levels. Objective 1: Hold six online professional development courses for 180 middle and high school teachers at underserved schools across the US. Objective 2: Present five or more dissemination workshops on the units at science teacher conferences. The middle school unit will address the NGSS topic of Structure and Function using microbes as a means to engage students in learning cell biology. The high school unit will address the Disciplinary Core Idea of Heredity: Inheritance and Variation of Traits, using human traits to learn about inheritance, sources of genetic variation, probability and risk. Each unit will integrate Science Practices and Crosscutting Concepts and both will focus on the Practice of engaging in argument from evidence. Once developed, the GSLC will hold online courses for 180 middle and high school teachers from underserved schools, providing experience with NGSS- aligned curricula via the units and building skills in evidence-based argumentation and other Practices. The project will leverage the GSLC's expertise in producing highly effective, NGSS-aligned curricula and professional development programs. The units will be broadly disseminated via our Learn.Genetics and Teach.Genetics websites, which are used annually by >18 million visitors who come from every country.